Proximity payment cards are in widespread use. A well known standard for such cards has been promulgated by MasterCard International Incorporated, the assignee hereof, and is referred to as “PayPass”. Proximity payment cards typically include a radio frequency identification (RFID) integrated circuit (IC) embedded in a card-shaped plastic body. An antenna is also embedded in the card body. The antenna allows the card to receive a power signal from a point of sale terminal. The antenna is also used by the RFID IC to transmit the payment card account number, and possibly other information as well, to the POS terminal.
It has been proposed to include in a proximity payment card a switch that may be actuated by being pressed by the cardholder's finger. Actuation of the switch may complete a circuit between the RFID IC and the antenna to allow the card to receive the power signal from the POS terminal. With this arrangement, the card is normally disabled (i.e., when the switch is not actuated), but can be enabled by actuating the switch when it is desired to present the card to the POS terminal. Because the card is normally disabled, it may be immune from attempts to surreptitiously interrogate the card in order to obtain the payment card account number for fraudulent purposes.
According to some proposals, a dimple may be formed on the outer surface of the card to indicate to the cardholder where to press the card to actuate the switch in order to enable the card for reading. However, providing a dimple on the card may increase the manufacturing cost of the card and may cause other disadvantages, including an increase in the thickness of the card.